[V3 Config] Implement a true clear method (#1344)

* Add clear methods to drivers

* Update config clear methods, add to Value

* Add test

redbot/core/config.py

@@ -146,6 +146,12 @@ class Value:
         """
         await self.driver.set(*self.identifiers, value=value)
 
+    async def clear(self):
+        """
+        Clears the value from record for the data element pointed to by `identifiers`.
+        """
+        await self.driver.clear(*self.identifiers)
+
 
 class Group(Value):
     """
@@ -438,14 +444,6 @@ class Group(Value):
         path = [str(p) for p in nested_path]
         await self.driver.set(*self.identifiers, *path, value=value)
 
-    async def clear(self):
-        """Wipe all data from this group.
-
-        If used on a global group, it will wipe all global data, but not
-        local data.
-        """
-        await self.set({})
-
 
 _config_cogrefs = {}
 _config_coreref = None
@@ -1037,7 +1035,7 @@ class Config:
                           driver=self.driver)
         else:
             group = self._get_base_group(*scopes)
-        await group.set({})
+        await group.clear()
 
     async def clear_all(self):
         """Clear all data from this Config instance.

redbot/core/drivers/red_base.py

@@ -1,5 +1,3 @@
-from typing import Tuple
-
 __all__ = ["BaseDriver"]
 
 
@@ -8,13 +6,18 @@ class BaseDriver:
         self.cog_name = cog_name
         self.unique_cog_identifier = None  # This is set by Config's init method
 
-    async def get(self, *identifiers: Tuple[str]):
+    async def get(self, *identifiers: str):
         """
         Finds the value indicate by the given identifiers.
 
-        :param identifiers:
+        Parameters
+        ----------
+        identifiers
             A list of identifiers that correspond to nested dict accesses.
-        :return:
+
+        Returns
+        -------
+        Any
             Stored value.
         """
         raise NotImplementedError
@@ -24,18 +27,34 @@ class BaseDriver:
         Asks users for additional configuration information necessary
         to use this config driver.
 
-        :return:
+        Returns
+        -------
             Dict of configuration details.
         """
         raise NotImplementedError
 
-    async def set(self, *identifiers: Tuple[str], value=None):
+    async def set(self, *identifiers: str, value=None):
         """
         Sets the value of the key indicated by the given identifiers.
 
-        :param identifiers:
+        Parameters
+        ----------
+        identifiers
             A list of identifiers that correspond to nested dict accesses.
-        :param value:
+        value
             Any JSON serializable python object.
         """
         raise NotImplementedError
+
+    async def clear(self, *identifiers: str):
+        """
+        Clears out the value specified by the given identifiers.
+
+        Equivalent to using ``del`` on a dict.
+
+        Parameters
+        ----------
+        identifiers
+            A list of identifiers that correspond to nested dict accesses.
+        """
+        raise NotImplementedError

redbot/core/drivers/red_json.py

@@ -58,3 +58,14 @@ class JSON(BaseDriver):
 
         partial[full_identifiers[-1]] = value
         await self.jsonIO._threadsafe_save_json(self.data)
+
+    async def clear(self, *identifiers: str):
+        partial = self.data
+        full_identifiers = (self.unique_cog_identifier, *identifiers)
+        for i in full_identifiers[:-1]:
+            if i not in partial:
+                break
+            partial = partial[i]
+        else:
+            del partial[identifiers[-1]]
+        await self.jsonIO._threadsafe_save_json(self.data)

redbot/core/drivers/red_mongo.py

@@ -71,7 +71,7 @@ class Mongo(BaseDriver):
         uuid, identifiers = identifiers[0], identifiers[1:]
         return uuid, identifiers
 
-    async def get(self, *identifiers: Tuple[str]):
+    async def get(self, *identifiers: str):
         await self._ensure_connected()
 
         mongo_collection = self.get_collection()
@@ -104,6 +104,17 @@ class Mongo(BaseDriver):
             upsert=True
         )
 
+    async def clear(self, *identifiers: str):
+        await self._ensure_connected()
+
+        dot_identifiers = '.'.join(identifiers)
+        mongo_collection = self.get_collection()
+
+        await mongo_collection.update_one(
+            {'_id': self.unique_cog_identifier},
+            update={"$unset": {dot_identifiers: 1}}
+        )
+
 
 def get_config_details():
     host = input("Enter host address: ")

tests/core/test_config.py

@@ -298,6 +298,16 @@ async def test_member_clear_all(config, member_factory):
     assert len(await config.all_members()) == 0
 
 
+@pytest.mark.asyncio
+async def test_clear_value(config_fr):
+    config_fr.register_global(foo=False)
+    await config_fr.foo.set(True)
+    await config_fr.foo.clear()
+
+    with pytest.raises(KeyError):
+        await config_fr.get_raw('foo')
+
+
 # Get All testing
 @pytest.mark.asyncio
 async def test_user_get_all_from_kind(config, user_factory):